Shade Happens: GHG emissions-driven analysis of BIPV strings under partial shading

Paper in proceeding, 2025

The interconnection of photovoltaic (PV) modules into series and parallel connections has garnered significant attention in the literature over the past decade. The connection is typically fixed for the system's service life and can heavily dictate the system's performance if it encounters partial shading. In building-based applications of PV, this issue has not received as much attention due to the prevalence of module-level power optimisers and microinverters as a solution to partial shading. However, these types of devices have the potential to negatively impact the carbon-emissions abatement potential of systems if not used with a critical lens to their life-cycle environmental impact. In this paper, we compare the system performance of seven different PV interconnection schemes using carbon payback time. We model a building-integrated photovoltaic (BIPV) facade and simulate its annual yield at an hourly timestep. We use a current and voltage curve approach to capture the impact of partial shading. We find that module-level optimiser-based systems are capable of generating enough electricity to offset the carbon emitted during their manufacturing in the context of Zurich, Switzerland. Furthermore, we discuss future research directions for BIPV string optimisation.